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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def call_graphviz_dot(src, fmt):
 """Call dot command, and provide helpful error message if we cannot find it. """

    try:
        svg = dot(src, T=fmt)
    except OSError as e:  # pragma: nocover
        if e.errno == 2:
            cli.error("""
               cannot find 'dot'

               pydeps calls dot (from graphviz) to create svg diagrams,
               please make sure that the dot executable is available
               on your path.
            """)
        raise
    return svg