diff --git a/Cargo.lock b/Cargo.lock
index 4221c6a..467b56a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -31,9 +31,9 @@ dependencies = [
 
 [[package]]
 name = "bindgen"
-version = "0.53.2"
+version = "0.53.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6bb26d6a69a335b8cb0e7c7e9775cd5666611dc50a37177c3f2cedcfc040e8c8"
+checksum = "c72a978d268b1d70b0e963217e60fdabd9523a941457a6c42a7315d15c7e89e5"
 dependencies = [
  "bitflags",
  "cexpr",
@@ -61,9 +61,9 @@ checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
 [[package]]
 name = "cc"
-version = "1.0.52"
+version = "1.0.54"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3d87b23d6a92cd03af510a5ade527033f6aa6fa92161e2d5863a907d4c5e31d"
+checksum = "7bbb73db36c1246e9034e307d0fba23f9a2e251faa47ade70c1bd252220c8311"
 
 [[package]]
 name = "cexpr"
@@ -136,9 +136,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.12"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "61565ff7aaace3525556587bd2dc31d4a07071957be715e63ce7b1eccf51a8f4"
+checksum = "91780f809e750b0a89f5544be56617ff6b1227ee485bcb06ebe10cdf89bd3b71"
 dependencies = [
  "libc",
 ]
@@ -166,9 +166,9 @@ checksum = "b294d6fa9ee409a054354afc4352b0b9ef7ca222c69b8812cbea9e7d2bf3783f"
 
 [[package]]
 name = "libc"
-version = "0.2.70"
+version = "0.2.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3baa92041a6fec78c687fa0cc2b3fae8884f743d672cf551bed1d6dac6988d0f"
+checksum = "9457b06509d27052635f90d6466700c65095fdf75409b3fbdd903e988b886f49"
 
 [[package]]
 name = "libloading"
@@ -212,6 +212,7 @@ dependencies = [
  "bindgen",
  "heck",
  "lazy_static",
+ "structopt",
 ]
 
 [[package]]
@@ -221,10 +222,36 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19b17cddbe7ec3f8bc800887bab5e717348c95ea2ca0b1bf0837fb964dc67099"
 
 [[package]]
-name = "proc-macro2"
-version = "1.0.12"
+name = "proc-macro-error"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8872cf6f48eee44265156c111456a700ab3483686b3f96df4cf5481c89157319"
+checksum = "98e9e4b82e0ef281812565ea4751049f1bdcdfccda7d3f459f2e138a40c08678"
+dependencies = [
+ "proc-macro-error-attr",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro-error-attr"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f5444ead4e9935abd7f27dc51f7e852a0569ac888096d5ec2499470794e2e53"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "syn-mid",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1502d12e458c49a4c9cbff560d0fe0060c252bc29799ed94ca2ed4bb665a0101"
 dependencies = [
  "unicode-xid",
 ]
@@ -237,9 +264,9 @@ checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
 
 [[package]]
 name = "quote"
-version = "1.0.5"
+version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42934bc9c8ab0d3b273a16d8551c8f0fcff46be73276ca083ec2414c15c4ba5e"
+checksum = "54a21852a652ad6f610c9510194f398ff6f8692e334fd1145fed931f7fbe44ea"
 dependencies = [
  "proc-macro2",
 ]
@@ -280,6 +307,52 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 
+[[package]]
+name = "structopt"
+version = "0.3.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "863246aaf5ddd0d6928dfeb1a9ca65f505599e4e1b399935ef7e75107516b4ef"
+dependencies = [
+ "clap",
+ "lazy_static",
+ "structopt-derive",
+]
+
+[[package]]
+name = "structopt-derive"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d239ca4b13aee7a2142e6795cbd69e457665ff8037aed33b3effdc430d2f927a"
+dependencies = [
+ "heck",
+ "proc-macro-error",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef781e621ee763a2a40721a8861ec519cb76966aee03bb5d00adb6a31dc1c1de"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
+[[package]]
+name = "syn-mid"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7be3539f6c128a931cf19dcee741c1af532c7fd387baa739c03dd2e96479338a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "termcolor"
 version = "1.1.0"
@@ -333,9 +406,9 @@ checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 
 [[package]]
 name = "version_check"
-version = "0.9.1"
+version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "078775d0255232fb988e6fccf26ddc9d1ac274299aaedcedce21c6f72cc533ce"
+checksum = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
 
 [[package]]
 name = "which"
diff --git a/Cargo.toml b/Cargo.toml
index 5410af7..447bfb9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,3 +12,6 @@ lazy_static = "1.4"
 [build-dependencies]
 bindgen = "0.53.2"
 heck = "0.3"
+
+[dev-dependencies]
+structopt = "0.3.14"
diff --git a/src/lib.rs b/src/lib.rs
index fd2749d..d4509b6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,7 @@
+use std::cell::RefCell;
 use std::ffi::{self, CStr, CString};
 use std::os::raw::c_char;
 use std::ptr;
-use std::cell::RefCell;
 
 pub mod sys;
 // Re-export enums
diff --git a/src/value.rs b/src/value.rs
index 98c9141..84e8630 100644
--- a/src/value.rs
+++ b/src/value.rs
@@ -1,3 +1,4 @@
+use std::fmt;
 use std::ffi::c_void;
 use std::ops::{Deref, DerefMut};
 
@@ -149,18 +150,15 @@ impl TensorInfo {
             symbolics.len() as u64
         );
         fixeds.into_iter().zip(symbolics).map(|(fixed, ptr)| {
-            if ptr.is_null() {
-                assert!(fixed >= 0);
+            if fixed >= 0 {
                 SymbolicDim::Fixed(fixed as usize)
             } else {
-                assert!(fixed == -1);
                 SymbolicDim::Symbolic(unsafe { CStr::from_ptr(ptr) })
             }
         })
     }
 }
 
-#[derive(Debug)]
 pub enum SymbolicDim<T> {
     Symbolic(T),
     Fixed(usize),
@@ -176,6 +174,16 @@ impl<T> SymbolicDim<T> {
     }
 }
 
+
+impl<T: fmt::Debug> fmt::Debug for SymbolicDim<T> {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            SymbolicDim::Symbolic(t) => write!(fmt, "{:?}", t),
+            SymbolicDim::Fixed(u) => write!(fmt, "{}", u),
+        }
+    }
+}
+
 pub struct Tensor<T> {
     /// If this is none then ort owns the data.
     owned: Option<Vec<T>>,